PCB connectors must be rugged, reliably transmit signals, and must not fail. Rugged PCB connectors must withstand mechanical, thermal, and chemical stresses such as: • shock, • vibration, • oscillation, • gas, • humidity, • high temperatures, • moisture, and • dust, without failing. Robust PCB connectors are essential in aerospace and aviation, industrial automation, the automotive industry and medical technology. Our PCB connectors withstand
these stresses through various proven methods. Our development department continuously optimizes our PCB connectors and ensures they are protected against additional environmental influences. Through numerous testing procedures, we ensure consistently high quality.
Mechanical stresses such as vibration, oscillation, and shock – No contact failure with rugged PCB connectors
Compatible contact system for rugged PCB connectors
Contact system: Double-sided spring-loaded connector for printed circuit boards
Double-sided spring contact One27 without (left) and with shock impact (right)
Our rugged PCB connectors feature a double-sided spring strip, which provides redundancy and ensures reliable contact for board-to-board connectors. Thanks to the second spring, signal transmission is guaranteed at all times via a contact point, even when the PCB connector is subjected to high shock loads. This ensures optimal device design.
By comparison, traditional two-piece PCB connectors rely on a single blade contact and a spring contact; under severe shock, the blade strip can lift off the spring strip and interrupt signal transmission.
Contact system: Gender-neutral contact system for PCB connectors
Zero8 Gender-Neutral Contact System
PCB connectors with a "gender-neutral" contact system are significantly more robust. The unique feature of this contact system is that the plug and socket halves have identical contact geometries. As a result, each pin is contacted by two springs, with the plug and socket interlocked so they cannot separate from one another. This provides maximum redundancy and makes our board-to-board connectors extremely robust and reliable. (Fig. 5).
Contact system: One-piece connector for printed circuit boards
flexilink single-piece connector
Only one-piece PCB connectors are even more robust than the gender-neutral contact system used in board-to-board connectors.
One-piece PCB connectors do away with the traditional two-piece contact design consisting of a male and female connector. They have no vulnerable contact area and are therefore extremely resistant to shock, vibration, moisture, dust, and environmental conditions.
One-piece board-to-board connectors are also suitable for potting and other processes designed to protect the components of the PCB connector. When combined with press-fit technology, robust, one-piece PCB connectors provide the most secure mechanical and electrical connection between two PCBs.
Appropriate contact design for rugged PCB connectors
One27 spring tulip after the stamping and bending process
Our robust PCB connectors make contact with the 90-degree bent spring bar.
Advantage: The PCB connector makes contact with the smooth, rolled surface rather than the uneven, sharp-edged underside of the punched strip created by the punching process. This prevents increased surface abrasion and reduces contact resistance.
In addition to the spring bar, the blade bar on the PCB connector must also be cleanly punched and processed to ensure that defective geometries do not interrupt the contact during shock, vibration, and oscillation.
Suitable insulating bodies for rugged PCB connectors
The Zero8 connector allows for a center offset of ±0.7 mm and an angular offset of 4 degrees.
The insulating bodies of our rugged PCB connectors are designed to provide perfect protection for the sensitive contacts inside the connector against shock, vibration, and oscillation. Tapered insertion surfaces on the insulator of the board-to-board connector compensate for misalignment of the PCBs during mating and allow the connector halves to be mated without damage in the event of axial or angular misalignment.
Tolerance range for rugged PCB connectors
Zero8's tolerance compensation in all directions
The tolerance range is another factor that influences the robustness of a PCB connector. If the PCB connector cannot compensate for small tolerances, mechanical micro-movements such as shock, vibration, and oscillation will lead to wear or damage to the connector over time. If a robust PCB connector has a floating function, it can compensate for up to ±0.4 mm even during operation. This feature is becoming increasingly important, especially when a PCB is populated with several different connectors.
Minimal corrosion and wear on the surface of rugged PCB connectors in harsh environments
Abrasion and corrosion of the contact surface
Similar to PCB terminals, connectors with copper pins can oxidize easily when exposed to oxygen and ambient humidity. Our surface treatment prevents oxidation of the connector pins by applying a protective layer. The robust board-to-board connectors from ept minimize surface abrasion. This results in less corrosion, less oxidation, and a long service life with many mating cycles.
How do we manage this despite micro-movements caused by shock, vibration, oscillation, gas, humidity, moisture, and dust?
High-quality, durable contact plating on our rugged PCB connectors
Smooth surface on the male and female connectors
The result is low contact resistance and, consequently, excellent signal transmission from robust connectors designed for printed circuit boards in harsh environments. This helps prevent poor electrical connections and signal degradation.
We use the following contact coatings, among others:
Despite rising prices, gold remains an extremely popular contact material for rugged printed circuit board connectors due to its corrosion resistance and excellent conductivity.
A nickel-phosphorus alloy with a gold flash coating offers a cost-effective alternative. When combined in specific proportions, these two materials exhibit the same positive properties as gold: high corrosion resistance, low wear, and perfect conductivity.
Gas, humidity, high temperatures, moisture, and dust – rugged PCB connectors with no contact failure
Connectors for printed circuit boards using the press-fit method
The press-fitting process
Using press-fit technology, we produce an extremely robust and contamination-resistant PCB connector that withstands vibration, shock, gas, humidity, moisture, and dust. Robust PCB connectors manufactured using press-fit technology have a failure-in-time (FIT) rate ten times lower than that of automatically soldered PCB connectors. They are used, for example, in airbag systems, ABS, and ESP modules, as signal transmission in these applications must not fail under any circumstances.
How? Press-fit technology generates maximum holding forces between the connector and the PCB with minimal insertion force. During the press-fit process, a press-fit pin with a larger diameter than the hole diameter is pressed into a through-hole in the PCB. In the press-fit zone, the connector pin is flexible so that the PCB is not deformed by physical forces during the press-fit process. A cold weld forms between the contact pin and the metallized PCB hole: a gas-tight, corrosion-resistant, low-resistance, and electrically conductive mechanical connection that is also suitable for potting. This technology is specified in DIN EN 60352-5 and remains contact-secure even under very high mechanical and thermal stresses, such as vibration, bending, moisture, dust, and temperature changes, and can withstand acceleration loads from shock of up to 200 G. G-forces define stresses that act on the human body, an object, or a vehicle due to changes in the magnitude and/or direction of velocity. By way of comparison: Upon re-entry into Earth’s atmosphere, a space capsule is subjected to a G-force of approximately 7 G.
Connectors for printed circuit boards using SMT (Surface Mount Technology)
Meniscus formation around the soldering foot of the One27
Another option for a stable and reliable connection between connectors and printed circuit boards is Surface Mount Technology (SMT). These connectors are often used in industrial applications and in Industry 4.0, particularly when printed circuit boards need to be populated on both sides or when the minimum clearance from components in the direction of force cannot be maintained. Our particularly robust PCB connectors for SMT applications comply with IPC Class 3 for use in high-performance electronics. In this class, signal transmission must never fail and must handle higher currents. According to the IPC-A-610 standard, a robust connection between the connector and the PCB must maintain the correct ratio of solder ball, solder pad, and solder paste.
This is how SMT works: The connectors are soldered to defined connection areas on the PCB—the solder pads—using solder paste. In the reflow oven, the solder is melted and then cured. An optimal solder joint (SMT) is characterized by uniform meniscus formation, and the contact must be completely surrounded by the solder meniscus to achieve the best holding forces on the PCB.
Small, compact, yet rugged miniature connectors for printed circuit boards
Our extensive expertise, gained through regular optimizations and developments, enables us to build increasingly smaller and more robust connectors for printed circuit boards. As a result, our board-to-board connectors are becoming more durable and capable, even as installation space continues to shrink. ept’s small, robust miniature PCB connectors guarantee fast, simple, and reliable signal transmission despite harsh environmental conditions such as shock, vibration, oscillation, high temperatures, and dust, and also ensure moisture protection for the PCB connector.
Using press-fit technology or Surface Mount Technology (SMT), our small, compact board-to-board connectors ensure a low failure rate and maximum retention forces. Despite their miniature size, these small yet robust PCB connectors are designed so that, for example, insertion chamfers on the insulator body protect the contacts in the event of axial or angular misalignment. During installation, insertion chamfers provide support to enable error-free mating of male and female connectors. This is achieved through the geometry of the contacts and insulator body.
Mechanical and electrical testing of connectors for printed circuit boards
There are a variety of testing procedures for board-to-board connectors, which may vary depending on the industrial environment. Our rugged PCB connectors undergo the following tests in particular:
Stress test for rugged connectors
During the stress test for rugged connectors, the dielectric strength and contact resistance are tested, for example, after 500 mating cycles, both before and after the stress test.
Environmental testing for rugged connectors
Climatic testing for rugged connectors involves determining whether exposure to temperatures such as -55 °C for several hours, followed by 125 °C, has a negative effect on the contact resistance of the PCB connector. This ensures that the PCB connector is temperature-resistant.
Temperature shock test for rugged connectors
The temperature shock test for rugged connectors verifies whether the board-to-board connector can withstand, for example, 100 rapid, extreme temperature changes—each lasting 30 minutes—by subjecting the connector to alternating heat and cold.
Mating Cycle Testing and Gaseous Contaminant Testing for Rugged Connectors
The mating cycle test and the corrosive gas test for rugged connectors verify whether center misalignment and angular misalignment, as well as the tolerance range, function properly in the mated state under practical conditions. The combination of mating cycle testing and corrosive gas testing ensures that the performance of the PCB connector—in terms of contact resistance and dielectric strength—has not deteriorated and that optimal protection against corrosive gases is guaranteed for the PCB connector.
